1. Field of the Invention
This invention relates to a disk cartridge for exchangeably accomodating a disk-shaped recording medium, such as an optical disk or magneto-optical disk.
2. Related Art Statement
Up to now, a disk shaped recording medium, such as a write-once type optical disk, has been used. This type of the disk is accommodated in a disk cartridge when attached to the recording and/or reproducing apparatus with a view mainly to preventing data signal record and/or reproduce errors caused by the signal recording surface being injured or contaminated due to contact directly with part of a loading mechanism or due to contact of hand or finger or deposition of dust and dirt during insertion into or detachment from the recording and/or reproducing apparatus.
In such disk cartridge in which the disk is accommodated in a cartridge when the disk is attached to the recording and/or reproducing apparatus, there is proposed in, for example, in U.S. Pat. No. 4,746,013, a disk-exchange type disk cartridge wherein, for enabling the disk to be exchanged as desired and for utilizing the cartridge more efficiently, a plurality of disks may be exchangeably attached to the recording and/or reproducing apparatus.
As this type of disk cartridge, the present Assignee has already proposed an arrangement shown in the specification and drawings of the Japanese laid open Patent Publication No. 57970/1988 or an arrangement shown in the specification and drawings of the Japanese Utility Model Application No. 86810/1988. The disk cartridge shown in these specifications and drawings is so arranged that a lid is provided at a disk insertion/detachment aperture formed in the rear surface of the main body of the cartridge accommodating the disk opposite to its front surface or shutter attachment surface for opening or closing the aperture, and that this lid is opened to enable disk exchange. The lid has an L-shaped cross-section for closing the disk insertion/attachment aperture extending from the upper rear surface towards the lateral rear surface of the main body of the cartridge, and is pivotally connected to the rear parts of the lateral walls of the main cartridge body by pivoltal engagement between pivot pins and engaging recesses, so as to be rotated in a direction normal to the plane of the main body of the cartridge. The aperture opening/closing lid has an engaging recess on the lower inner rear surface which may be engaged with a mating projection on the rear edge of the main body of the cartridge when the lid is brought to a position of closing the disk insertion/detachment aperture.
With the above described disk cartridge, disk exchange may be made upon opening and closing the aperture opening/closing lid, while the disk cartridge may be attached to the recording and/or reproducing apparatus in the similar manner to the ordinary disk cartridge by closing the disk insertion/detachment aperture by the opening/closing lid.
The aperture opening/closing lid of the above described disk cartridge is rotatably supported by the main body of the cartridge by means of pivots on its both sides, so that a thrust pressure is necessarily applied to the central flat surface section intermediate both side pivots when the lid is opened by disengaging the engaging recess away from the mating projection of the main body of the cartridge. As a result, the upper central surface of the lid and the upper surface zone of the main body of the cartridge about the disk insertion/detachment aperture are flexed severely towards the inside of the main body of the disk cartridge. With the aperture opening/closing lid or the main body of the cartridge being thus flexed inwardly of the disk cartridge, there is the risk that the disk accommodating space in the main body of the cartridge becomes straightened to injure the accommodated disk. There is also the risk that the disk cartridge as a whole is deformed to interfere with smooth insertion and detachment of the disk cartridge into or from the recording/reproducing apparatus, and that, in addition, the disk is brought into contact with the main body of the cartridge upon rotation of the disk to cause damages to the disk.